McNamara airway cephalometrics assess UPA, LPA, and soft-palate length PNS–Et on the lateral cephalogram. James A. McNamara Jr. linked lateral pharyngeal dimensions to skeletal context SNA, SNB, and ANB. CephCalc records the airway block next to jaw angles. Try it in practice with retrognathia and snoring on the same film as skeletal McNamara. Pharyngeal screening on lateral ceph, not polysomnography.
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About the method
McNamara airway cephalometry quantifies upper and lower pharyngeal width and soft-palate length on the lateral cephalogram. James A. McNamara Jr. linked UPA, LPA, and segment PNS–Et to tracing Ptm, PNSair, Rgn, Et, and adjacent pharyngeal landmarks. Measures use lateral projection and complement skeletal context SNA, SNB, and ANB. CephCalc records the airway block beside jaw angles without re-uploading the image. Check soft-tissue contrast on the source image. Record airway measures at start and retention when maxillary expansion is planned.
What the analysis focuses on
UPA and LPA, soft-palate length PNS–Et, basic sagittal angles for orthodontic background.
When to use it clinically
Supports screening for pharyngeal narrowing with suspected sleep-disordered breathing and in orthodontic cases with retrognathia. Does not replace polysomnography or CBCT — it is a lateral projection reference. With a narrow airway often add McNamara jaw lengths and Jarabak vertical. Tie interpretation to snoring, daytime sleepiness, and nasal breathing exam. On case review, match the CephCalc table with profile photos, models, and TMJ exam: numbers without context are easy to misread. Repeat airway on retention cephalograms. Save airway PDF for consultation.
PNS-Et: PNS–Et (mm) — soft-palate length from PNS to the uvula tip
SNA: ∠ SNA — angle between lines S–N and A–N (maxillary position relative to the cranial base)
SNB: ∠ SNB — angle between lines S–N and B–N (mandibular position)
ANB: ∠ ANB — difference in jaw positions: angle between B–N and A–N
UPA, LPA, and PNS–Et for training
UPA and LPA quantify pharyngeal size on the lateral projection. PNS–Et estimates soft-palate length. Students should link narrow airway with SNB and profile on one review.
UPA — upper pharyngeal airway
LPA — lower pharyngeal airway
PNS–Et — soft palate length
SNA, SNB, ANB — context
Pharyngeal landmarks and errors
Pharyngeal contrast on cephs is often low. Do not invent outline without noting quality. Repeat film with correct head position improves measurement.
Ptm, PNSair — upper region
Rgn — lower region
Et — soft palate tip
Occlusion and tongue position
Limits and related methods
The airway preset does not treat OSA. CephCalc stores values in the chart for follow-up after orthodontic or surgical care.
McNamara — jaw lengths
CBCT — 3D airway
Jarabak — vertical and growth
PSG — sleep diagnosis
Try it in practice — free
Try it in practice
Upload a lateral cephalogram to CephCalc, place the landmarks, and run the McNamara airways analysis online — no software to install. Try it in practice free.
Ready-made method preset on your radiograph
Table of angular and linear measurements with race-specific reference norms (Caucasoid, East Asian, African)
In CephCalc select McNamara airways and mark Ptm, PNSair, Rgn, Et, and related pharyngeal landmarks. UPA, LPA, and PNS–Et appear with PDF export.
Does cephalometrics replace polysomnography?
No. Pharyngeal cephalometrics on the lateral film does not replace polysomnography or CBCT. It is a screening guide on the lateral projection at orthodontic exam.
How should a resident read UPA and LPA?
UPA describes the upper pharynx, LPA the lower. Match values with snoring and daytime sleepiness. Record both next to SNA and SNB in the chart.
Which landmarks are needed?
Ptm, PNSair, Rgn, Et, and points for UPA and LPA by McNamara rules. Pharyngeal outline quality on the film affects repeatability.
What combines with the airway preset?
Combine with skeletal McNamara for jaw lengths, Jarabak for vertical relations, and sleep medicine referral when OSA is suspected.
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